Structured interviews were administered, and blood samples were collected and tested for HIV, syphilis, and hepatitis B. The sample included 17.9 percent homosexual, 46.4 percent heterosexual, and 35.7 percent bisexually identified men. Results revealed that congruence between the prostitutes' nonpaid sexual behavior and their sexual self-identification were closest for the men self-identified as heterosexual and homosexual. The significant demographic and occupational differences between the prostitutes in each sexual self-identity category included education, history of physical abuse, homelessness, and geographical mobility. Based on self-identification, the rate of HIV infection was 50 percent for the homosexuals, 36.5 percent for the bisexuals, and 18.5 percent for the heterosexuals. The differences in HIV infection rates between the men of each sexual category were significantly related to self-reported receptive anal sex, number of nonpaid sexual partners, cocaine use, injection drug use, acquaintance with a person with AIDS, history of syphilis, and history of hepatitis. Sexual self-identity was not a significant predictor of HIV status. Tables and 18 references (Author abstract modified)